Physicists Discover New Quantum Bound State Involving Three Atoms

A team of physicists led by Professor Brett Esry at the Kansas State University have identified a new quantum bound state.

In this bound state that the team has labeled as “our state”, three atoms are bound loosely, exhibiting a familiar behavior in quantum mechanics known as the three-body bound states. This new state can be compared to the three body state predicted by Russian physicist Vitaly Efimov in the 1970s. Efimov’s quantum state could however be observed only in 2006 through an experiment involving ultra cold atomic gases. Such temperature conditions measuring higher than absolute zero by just one-billionth of a degree Kelvin can be established only in certain laboratories in the world. Esry’s quantum state also requires such a temperature condition for existence.

The three body bound state is such that three atoms can stick together but two atoms cannot. The three atoms remain bound even if two of the atoms repel each other. Matter can be classified into two particles, namely, bosons and fermions. While Efimov’s quantum state has been found to occur only with bosons, the state discovered by Esry’s team is applicable to both fermions and bosons. The forces of interaction between particles are of two types, viz. short ranged interaction and long ranged interactions. The range refers to the distance required for interactions to be effective. While Efimov’s state is confined only to short ranged interactions, the new quantum state is on the border between long and short ranged interactions.

The discovery may find applications in experiments employing ultra cold atomic gases. Esry’s team will continue to research the new bound state by studying the behavior of boson and fermion combinations in that state.